DE2454046A1 - METHOD OF INJECTING A RELATIVELY SMALL SAMPLE LIQUID INTO A CONTINUOUS FLOW OF LIQUID AND INJECTOR TO PERFORM THE PROCEDURE - Google Patents

Description

.- PHYS. F. FINALLY soj4 ontehpfaffunkofc: « 14.-NoV. 1974

PATENT Attorney postfa-h 1 / a

2454046 ™ ^N < ^{Munich) a} « ^{36 3e}

TELEGRAM ADDRESS: _{PATENDUCH HOtiC} HEN D1PL.-PHYS. F. FINALLY, D-8034 UNTERPFAFFENHOFEN. POST BOX CABLE ADDRESS:

TELEX 5 212 3OS PATE

Attorney's File: W-3636

Applicant: Waters Associates, Xnc.

Milford, Massachusetts / USA

Method of injecting a relatively small liquid sample into a continuous stream of liquid and injection device for implementation

initiation of the procedure

The invention relates to a method for injecting a relatively small liquid sample into a continuous one Liquid flow according to the preamble of claim 1 and further relates to an injection device in FIG Form of a multi-part valve device for carrying out the method.

It has long been difficult to effectively inject small amounts of liquid into high pressure liquid streams in such a way as to avoid undue dilution or reduction in concentration of the liquid in the stream
in which it is to be injected.

The most widely used and most widespread method of eliminating this difficulty has been -

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stood to use a hypodermic needle which by an elastic or a partition made of an EIa stomer is pushed through, which in turn is held in a predetermined position by means of a threaded cap. This method has the advantage that the sample is fed directly to the desired location, for example the inlet of a chromatographic Column is easy to carry out and that no dead space valves are used. However, this method has on the other hand, the disadvantage that the pressure is limited, i.e. it can, since there is frequent or regular reflux due to from leakage through the partition wall, cannot be operated reliably at high pressures. Also requires this method has a high dexterity to prevent the occurrence of such backflow due to Reduce leakage losses under high pressure to a minimum. On top of that, the partitions generally fall off after five to ten uses; even extremely skilled professionals can only do about fifty injections with the same partition wall at moderate pressure values. Even if the aforementioned difficulties are overcome the method in which a partition is used would still be suitable for many sensitive applications do not work properly because elastic polymers generally allow chemical components to seep through, which contaminate the samples to be injected. There are, however, some relatively inert chemical polymers; However these in turn tend to have lower or below average elastic properties and are leaking or leaking even more frequently. High pressure spraying do not help much in such cases, as it is not only the syringe seals that tend to leak, which is a (certain) Loss of the sample has the consequence, but also a volume compression or compression factor when using it results which interferes with an accurate sample measurement.

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In many applications, the influence of the aforementioned is sufficient Difficulties arise in order to noticeably reduce the value of these processes and thus also of liquid chromatography. For example, in liquid chromatography, the value of a sample in terms of cost for the work and production time that is expended to separate or separate the sample or synthetically cost thousands or even tens of thousands of dollars to manufacture. Loss or pollution of any of the above Rehearsing is therefore a disaster in the course of an investigation. Not about the risk of such a loss a scientist prefers to use less with less Analytical procedures prone to risk, although they can be more expensive and less accurate.

Consequently, they are in the field of liquid chromatography significant efforts and efforts in the development and construction of improved sample injectors has been expended. Such devices are described, for example, in US Patents 3,505,862, 3,37,660 and 3,631,724 described. However, none of these devices can satisfy the demand for a reliable method small amounts of liquid in a high pressure flow system to be injected without causing any contamination, pressure instability due to compression or compression loss in the system and an unfavorable sample distribution in the column due to an excessive long introduction due to a so-called "peak spread" he follows. The so-called "peak spread" is based on the fact or is due to the process that the sample is excessively diluted in the injection device before it enters the column. Hence, the peaks that appear on an analytical chart are the composition leaving the column reproduced, less clearly or sharply, i.e. they are converted into lower, more difficult to define forms.

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walked or spread ".

When trying to create facilities with the required reliability, relatively rigid or non-compliant plastic or synthetic resin materials have been used (here, under "relatively rigid or non-compliant "rigid in contrast to elastic or elastomeric synthetic polymers such as they used for seals in normal printing). These rigid or non-compliant materials are used in the Manufacture of seat surfaces or other seal designs for valves used in injection mechanisms will. However, difficulties have also arisen in the use of such materials; they tend namely to absorb (and desorb) part of the broad spectrum of chemical compounds which can be expected through a contact or a touch. This embodiment tends not only to its dimensions but also to create a source of pollution. In part, this also leads to a cooling of the current at high pressures. This results even with such relatively creep-resistant materials, such as materials Polyacetal a greater difficulty when ver tries to introduce them into very small valves to the To moderate the flow or the flow of divided sample amounts in the microliter range. *Understood

Another method, the difficulty of injecting sample in chromatographic investigations to resolve "represents the inertia of a liquid which is injected into a capsule, which in turn is mounted i in the stream of the inflowing flui ⁵ and breaks. In the case of the sent process, the difficulty of contamination again plays a major role {even fingerprints on the capsule can lead to difficulties. In addition, the release must be immediate so that no sample is received

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remains attached to the capsule material and is thus lost. The capsule must also be completely filled so that the Difficulties with regard to compressibility are excluded; consequently need for different large samples, capsules of different sizes can also be used. In general, this method is not for the sensitive Suitable for liquid chromatography applications. However, it has some uptake in gas chromatography found.

In view of the costs and the achievable advantages, the current state of the injection device is best explained with reference to a valve with six openings, which is manufactured by the applicant under the trade name C906. This valve will operate adequately at ambient temperatures up to about JO kg / cm (1000 psi). In one embodiment of the valve, it is possible to inject samples into a separate loop line, although a pump is continuously feeding the chromatographic column. After the injection has ended, the valve is switched to a position in which the liquid in the column is conveyed through the loop line and introduced into the chromatograph. But even the-

/ be ^

These valves are only I50 C for an operation above 21 kg / cm (300 psi) recommended.

A suggestion from other manufacturers in this area seems to be the development of (particularly) small valves, which actually serve as sample holding devices, such as a gate valve such as that disclosed in U.S. Pat 3 7 ^ 8 833 is described which pivoted or off a sample receiving position can be moved into a position in which the samples are rinsed out. These bodies however, they are not particularly advantageous because they depend on the elastomers for sealing limits such a dependency, however, affects the sta-

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reliability of the design of the valves because of or with regard to a cold flow.

As a result, there is currently no facility available to inject small amounts of liquid into high pressure systems. without an undesirably high risk of losing, contaminating or diluting the sample, or that the constant pressure in the system is also lost. Furthermore, no device is currently available in stores, which is reliable at pressures of over 210 kg / cm (3000 psi) operated up to 420 kg / cm (6000 psi) or even higher can be.

According to the invention, therefore, a method and a Direction for injecting small liquid samples into a high pressure fluid system are created, which or which has at least one, but advantageously more than one of the following features, namely

(1) minimal dead space, i.e. the ability to actually expel all of the sample from the device;

(2) a means to dilute the sample based on its contact with the injector before it ejected from this, minimizes practically completely eliminating - i.e. the peak spread reduced to a minimum;

(3) a relatively simple structure so that it can be easily disassembled for maintenance and monitoring or inspection purposes; ik) suitability not to wet the elastomeric surfaces during use;

(5) not to leak over an improved temperature range and at pressures up to and above 210 kg / cm (6000 psi);

(6) Can be used for samples up to a fraction of a microliter to be; .

(7) overpressure protection for valve elements;

(8) ease of use; and

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(9) the possibility of a wide range of sizes. To inject samples, whereby the above under (l), (2) and (6) the listed advantages are retained.

The above objectives are essentially achieved through the development of a multi-part valve (i.e. a valve with a large number of valve elements) he has been enough. According to the invention there is thus a method and means have been created to efficiently take fluid samples inject into high pressure fluid systems; here the device is particularly advantageous in connection usable with liquid chromatography systems and is characterized in that by filling a sample

guidance from a point directly at the outlet of the injection device from the size of the sample or loop line is increased incrementally or additionally, since it is farther away from the filling point »and that that Pressure reducing and thus the dead space, which is normally related to the pressure reducing, is reduced to a minimum is. * from backwards

The invention is described below on the basis of a preferred embodiment with reference to the accompanying drawings explained in detail, without thereby any Modifications or within the scope of the invention Abwand lungs should be excluded. Show it:

Fig.l from below is a view of an injection valve device according to the invention, some details are shown schematically in the view to to facilitate their description;

FIG. 2 is a sectional view along the line 2-2 in FIG. whereby . but only the branching or distribution block shown and reversed right and left;

ft

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3 in plan view a sectional view through the branching or distribution section of the device in Fig.l and 2;

Fig. 4 to 4C a valve, which is particularly useful for the rubbing. tion the Fig. 1 is used}

5 shows a schematic representation of a sample injection scheme according to the invention; and

6 and 6a schematically sample lines, which in the Device according to the invention can be used.

Xn Fig.l an injection valve device 20 is shown, which has a central branch or distributor part 22, a rear valve part 24, a valve actuator 26 with a valve actuator part 28, a Ven tilspindel JO and a valve actuator block 32 has . In addition, a valve closure part 34 arranged on the front side provides access to an injection opening 36. By means of a valve actuating handle 38, flow paths through a line system in the branching steep 22 are selected, as will be described in detail below.

The branching or distributor part 22 has an inlet 40 through which a liquid enters the branching part is introduced. The inlet 40 is always (via a valve 4l, a main line 42 and a valve 43) with a Outlet 49 in connection. Furthermore, the inlet 40 is with a Secondary or secondary line 44 in connection when the valve 4l is in the open position.

The secondary or secondary line 44 is connected to a line receiving the sample, which is hereinafter referred to as sample line46 is referred to in connection. By means of a through

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the handle 38 actuatable vent valve 48 may be a Passage between one end 45 of the sample line 46 and a vent 50, i.e. an outlet or a drainage opening can be opened. The use of this vent is discussed elsewhere in the description described.

The end 47 of the sample line 46 is connected to the sample injection port 36 in connection. The connection between the Sample line 46 and the injection port 36 is located immediately next to an inlet to a valve 43 · If that Valve 43 is open, the sample line 46 is in communication with the outlet 49.

The sample line 46 runs like this. as shown in the reproduced embodiment of the invention, in essentially to the outer surface of a membrane 85 (see FIGS. 4 to 4 b) which forms part of the valve 43. Just like that the sample injection port 36 extends almost up to the outer surface of the same membrane as the sample injection advantageously see with the help of a hypodermati Needle assembly is performed with the needle extending into conduit section 46. Xn such a Position, the sample line 46 forms a concentric circle in the line section 46a and fills the ring, wel rather is formed by the wall of this line and the hypodermic needle. The sample is injected in reverse from the hypodermic needle in the immediate vicinity of valve 43 · The importance and therefore the Significance of this feature, namely that the sample injection port and the sample line are both directly associated with the valve 43> i.e. end directly at the outlet 49, is to be seen in the fact that thereby a. Filling in the sample is ensured or guaranteed in the sample line, as will be explained in detail later, »from backwards

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In Fig.2 and 3 are the branching or distribution part and the positions in the various pipe and valve connections provided for it. As in Fig.l are the Line 42 and sample line 46 are shown schematically. In a central opening 51, the valve actuation device is 26 housed, which is used to open and close the valves 4l and 43, as will be described below will. In openings 52 and 54 are connecting or connecting parts are used, which the valves 4l or Connect 43 to line 42. In openings 55 and 56 are further connection parts are provided in order to connect the sample line 46 to the injection opening 36 and the valve 48. The connecting parts themselves are designed in a conventional manner, but do not constitute an essential part of the subject of the application and are therefore not shown in the drawings.

As shown in Fig.l, the parts 22, 24 and 34 are through Nuts and bolts are kept under pressure, which, although not shown, is readily apparent to those skilled in the art is to be understood.

From Figure 2 it can also be seen that three openings 60, 61 or 62 on the left side and three openings 63, 64 and 65 on the right side of the branch part 22 vorgese hen are. These groups of openings represent F / luid accesses to the valve 43 or 4l.

In a corresponding manner, an opening 66 is shown in FIG the left side and two openings 67 and 68 on the right side of the branch part. About the opening 66 the sample fluid is introduced into the valve 43. Openings 67 and 68 are used as part of the vent valve 48. Here, the opening 67 is on the sample line 46 is connected to the opening 61 and the opening 68 is connected to the outlet or the discharge opening 50.

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As can again be seen from Fig.1, is in the on the Valve part 34 arranged on the front side is screwed in a closing part 80, in which a type of container in the axial direction 82 is arranged for an injection device, for example a hypodermic needle. Such a one The needle is not shown in the drawings as it is known to those skilled in the art. To inject A stopper or plug 81 is removed from a sample by unscrewing it and becomes a Syringe inserted into closure part 80. This is done as long as valves 43 and 41 are closed, so that the entire liquid flowing into the inlet 40 speed via the main line 42 is conveyed further. The hypodermic syringe is arranged so that its needle passes through a polymeric sealing member 84 and is near the outer surface of the membrane 85} there by releasing the valve .48 the outlet 50 to the sample line 46 is open, the sample is introduced into the sample line 46. The sample liquid is from the End of the line 46a, which is close to the valve 48, is filled into the sample line 46 from the rear. Displaced fluid is then expelled via outlet 50. When the introduction or filling into the sample line 46 is completed and the syringe is withdrawn, the Plug or stopper reinserted and the vent opening closed; then the valves 4l and 43 open, and because of the flow resistance due to the length and the relatively small diameter of the sample line 46, the flow flows from the inlet 40 via the Line 44, «the valve 48, the sample line 46 and via its end 46a directly via the outlet 49, for example into a column of a chromatograph.

On the other side of the one placed on the front Valve part 34 is a device 38 for actuating the Valve 48 is provided. This facility is also in

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screwed in the valve part arranged on the front side 3 ^. By screwing into the thread Ö6, the speed is controlled at which the loading

/ 88 push button 87 of the plunger piston forward to close the valve 48. As stated above, finds all liquid flow from valve 41 to valve 43 when valve 48 is open via the valve 48 instead. A new valve that can be used in connection with the invention will now be described with reference to FIG to 4b.

However, before the valve is described in detail, the advantageous features of this valve are described below specified:

(a) the valve has practically no excess, i.e. beyond the required volume, which does not serve to reduce its flow volume or capacity to enlarge.

(b) The valve does not have any conventional elastic or elastomeric components, but has a thin one, less as a coating or equivalent of about 0.005 cm (0.002 inches), and preferably about 0.0025 cm (0.001 inch) Support made of a deformable or plastic material, for example a lead-gold-copper or polymer support or a corresponding coating similar to a polytetrafluorethylene coating, on part of it. Polytetrafluoroethylene is preferably used because of its chemical resistance or resistance, but lasts generally a thin elastic or elastomeric coating or a corresponding coating to an excessive There was a tendency to diverge at high pressures.

(c) There is also virtually no dead space in the valve; Here, "dead space" means a volume in which you hang liquid will settle and withstand quick removal or disposal by flushing the valve can. The valve shown has no dead space and

-4 3 only has a volume to be flushed of about 16.4.10 cm ^J

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(O ₁ OOOl in) to} even this volume can be reduced to a small fraction of this without any problem.

(d) The valve can be quickly switched between open and closed by means of a bi-directional mechanism Positions are moved, which makes it particularly suitable for automatic controls.

(e) Either it is irrelevant or the valve structure promotes mixing or a disruptive influence on the Liquid flow not at all.

(f) Rather, the valve provides an effective means of connecting a fluid to an existing one Allows flow path. That way it doesn't meet only the function of a valve but is also a T-shaped connection in a pipe system.

(g) In addition, the valve can be easily inspected, checked and, if necessary, replaced.

The thin stainless steel disc acts as a seal an approximately 0.0025cm (QDO1 inch) thick polytetrafluoroethylene pad on. In fact, this disc acts as a seal and a membrane at the same time, as the support resp. the coating serves as a seal in high pressure applications.

In Figures k through kB , a valve 100 is shown having a generally flat, thin metal disk 16 with positioning lugs 102 having openings 103, thereby providing means for adjusting the valve in the construction of an assembly. The adjustment gauges are mounted somewhat recessed in the embodiment shown. The main part 104 of the valve has an actuating disk 1θ6 which has a diaphragm made of stainless steel and a coating or coating made of a corrosion-resistant, chemically inert polymer 107 on its outer, wetted, annular surface 109. The disc 106 also has a circular recess on its front side

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108 through which a flow path 110 is formed. The valve also has a single surface 112a of the Housing required for the operation inlet and outlet lines «for example 63 to 65 on.

A valve operating rod 105 is mounted centrally with respect to the disk IO6 to hold it in contact with the housing 112 to bend down. If the disc can be flexed away from the housing 112, the fluid can flow into (or, as in the illustrated device) the valve assembly from a centrally located port 64 flow, which is blocked ver by a central sealing surface 114 when the disc is bent towards the opening 64 is.

The mode of operation of these valves can best be described with reference to valve 100 when it is shown in Fig.l as a valve 4l is used. When the disc is in its closed position, i.e. the center sealing surface 114 pressed against the line 64 by the actuating rod I05 fluid can flow from inlet 40 through inlet port 65 via the circumferential recess 108 and the conduit formed by the housing part 112a flow halfway around the surface 114 and over the outlet opening 63, which serves as the outlet part of the valve. If so, then the disk can take up its normal and not bent position again, the surface 114 is withdrawn and no longer lies against the opening 64 through the opening Liquid flowing in 65 then flows freely through the opening 64 and through the opening 63. (When actuated of the valve 4l, of course, due to the flow resistance in the line 42, essentially the entire liquid flow flows through the opening 64 and not through the opening 63).

For most facility use cases, the

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Valves 4l and 43 be open and closed at the same time. For this reason it is advantageous that the valves each have the same structure, although the properties of the Valve are only important and of fundamental importance when it is, as with the valve 43 in Fig.l, between the sample line 46 and outlet 49 is used, the injected sample then flowing over the valve. (In addition to this fundamental importance with regard to avoiding the peak spreading or broadening and one Loss of sample, the main advantages are that it can be easily flushed, little maintenance or upkeep requires, etc .; this of course applies to the valve when it is in use, and these provide advantages in the actual intended use in the device shown in Fig.l to 3.

If the valves 4l and 43 work simultaneously, it is important that a corresponding closing is ensured without overpressure on the valve disks. As shown in FIG. 1, this is achieved by means of a handle 28 which is attached to a pull rod $ 0 . The pull rod is keyed in the valve operating block 32 and the rear valve part 24 for the purpose of displacement. Therefore, when the handle 28 is rotated, this is transmitted to the block which pushes or displaces the actuating rods 105 against the diaphragms of the valves. A number of spring washers 91 are mounted between a nut 92 and the block 32 to ensure that there is no overpressure on the diaphragms.

In the multi-part valve device according to the invention, the housing for the diaphragm valve and the required Inlets and outlets are advantageously formed by the distributor or branching part 22 and the valve part 24. In addition, a flow bypass line is provided in the device shown. Still it could

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Valve can be modified in such a way that the continuous bypass line is omitted by removing the circular recess is no longer provided.

Another advantage of the illustrated embodiment of the invention is that no valve is required in line 42 to shut off or deflect the flow through the sample line. This is achieved by the formation of the line 42, which represents a much higher resistance for the Pluidstrom than the sample line. This is achieved in an advantageous manner without using impermissible fluid mixing devices, ie openings, nozzles or something similar. This is preferably achieved by a line with a smaller diameter in order to ensure a sufficiently high, corresponding resistance in the line 42. In general, it is also desirable that the resistance shown schematically in Fig. 1 at 42R is dimensioned such that a flow in the line 42 is less than 25% of the flow in the sample line. In the best embodiments of the invention, the flow is less than 1% of the flow in the sample line.

Another device to very beneficial the flow resistance To control in the main line consists in the use of a pre-sensed flow resistance, for example a spring-loaded shut-off valve which generally closes when pressure is released and the flow is directed through the sample line. Such a device enables the handling of extremely high flow changes. In general, the method in which manual actuation of a flow-holding device in the main line 42 Avoided is avoided the very difficult problem of order.

Another advantage of the invention is that of

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is back filled, i.e. a method is used in which the sample line is filled from the back, i.e. from the. End, which is located immediately at the outlet 49, in the direction on the opposite end 45 of the sample line 46 is filled. It has been found that the advantage of this new design or arrangement is that even the smallest injected sample, for example a sample which partially occupies the annular space in the Line section 46a, which would be filled by a hypodermic needle and the wall of the line section 56 is set, discharged through the valve 43 and the opening 49 which are a flow (plug-flow) increment comes as close as possible. Larger increments or increases only fill the space they require and do not have to flow through any unnecessary conduit when they are removed from the Sample line are ejected. As a result, the so-called peak spreading or broadening is to a minimum degraded.

A third advantage of the illustrated embodiment of the invention, which is particularly useful and applicable in connection with the above-mentioned filling from the back, consists in the use of a sample line, which has segments or sections with an increasing cross-section, the further the sample line extends from the point of sample injection. Because of this training, which shown schematically in FIGS. 6 and 6A, larger samples can be injected without the undesired Spreading of such a larger sample takes place, which is due to the friction between the sample and the walls of the necessarily longer segments would be caused by smaller conduits of comparable volume. One execution for increasing the volume of a sample line for example: would consist of (a) a section 0.5 cm (0.2 inches) long has a diameter of 0.05 cm (0.02 inches) a section 12.7 cm (5 inches) long

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0.076cm (0.03 inches) diameter, (c) one section 15 inches long and 0.14cm in diameter (0.045 inches). In connection with such a Sample line could be a main line with an inner diameter of 0.023cm (0.009 inches) and 0.9m (3rd feet) length can be used to achieve a sufficient flow resistance and thereby the flow to pass through the sample line.

In FIGS. 6 and 6A this is with regard to the ends 46a and 45 a sample line, as shown in Fig.l. In Figure 6 is a series of sections l46a to l46d a sample line 146 is shown, the diameter of which is increasing, the further the section of the sample line is from the end 46a (at which the sample first enters the Sample line injected in the middle of a syringe and attached which the sample will later be ejected). A similar sample line 246 is shown schematically in FIG. 6A, in which the diameters become larger gradually, thereby causing some influences on insertion on the flow between the sections with different diameters is reduced and thereby any itself resulting peak spreading effect is further reduced.

In Figure 5 is a schematic representation of the flow pattern an injector of the invention shown, which in conjunction with. a liquid chromatography system I30 is used. Is used. As already shown above has been, a main object of the invention is to provide a reliable and safe injection smaller Obtain liquid samples in the inlet stream on a chromatographic column, for example at 132. The material flows through the column and, when it exits, is subjected to an analysis, for example by means of a refractometer 134. A recording or registering device assigned to this I36 is usually used to to provide a graphical representation of the analysis. The-

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This scheme is well known.

In Figure 5, an injection device I38 is shown which has a sample line 139 and a main line ΙΛΟ. The main line 140 contains a flow restriction device R, which is used to ensure that a state is reached on the main line so that the entire flow can be diverted or diverted via line 139 when line 139 is "open". In the. preferred embodiment of the above-described Invention, the flow throttling device R is the line itself, since the line is chosen so that it one has a much smaller diameter than the sample line 139 · Of course, this can also be done with valves or others Flow restrictors can be achieved by the required flow resistance R in the line l40 is used.

In normal operation a carrier fluid flows through line 14: 0 and valves 14l and 1 ^ 3 are closed to ensure that the flow passes through line 140. Next, the valves Ikk and Ik5 are opened and the sample liquid is injected through the valve ikk into the line 139 in the direction of the valve 1 ^ 5. Any excess liquid can escape from the system via valve 145 when the liquid is injected into line 139. Then the two valves ikk and 145 are closed} each of the valves 1 ^ 3 and 14l is then open, and the flow of the carrier liquid is diverted via the valve 14l, the line 139, the valve to the column I32.

Patent claims

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Claims (12)

"20" 2454048 Patent claims 1. Method of injecting a relatively small Liquid sample in a continuous liquid stream, through which the sample is sent to a liquid chromatograph is conveyed, the sample being introduced into a long stretched line holding the sample and the Flow of the carrier fluid is diverted from its normal flow path via the elongated conduit to the sample to convey into the chromatograph, characterized in that the sample in the holding the sample Device (46} 139) is injected so that it from this end (46a) of the sample line (46) which very is close to the chromatograph, flows to the opposite end (45) of the sample line (46; 139), while the Sample line is vented at its opposite end (45). 2. The method according to claim 1, characterized in that the flow of the carrier fluid over the Sample line (46; 139) is deflected in that a valve (41} l4l) between the normal flow path of the carrier fluid and the sample line (46; 139) and another valve (43 $ 143) between the sample line (46} 139) and the column (132) is opened, blocking the normal flow of carrier fluid without any further steps will. 3. Injection device in the form of a multi-part valve device for carrying out the method, characterized by a main inlet valve / (4l). a main exhaust valve (43) ^ a main line (42) between the main inlet and exhaust valves, through an additional inlet (36), through a sample line (46), which the additional - 21 - 509820/1058 Inlet (36) connects to the main inlet valve (4l) through valve means (42R) to divert at least a major portion of the flow from the main line (42) via the sample line (46) to divert, and through valve means, (48) to vent the sample line (46), the sample line (46) communicates with both the main exhaust valve (43) and the additional inlet (36) which is arranged immediately next to the outlet valve (43) so that the sample line (46) represents a device which a liquid sample at the input point "close to the outlet valve (43) in the direction of the venting device (48) receives out, which is arranged relatively far from the outlet valve (49). 4. Injection device for a chromatograph, with a separation column, which is connected to a supply device for the carrier liquid in order to produce a continuous flow through the column, and with a device to inject liquid samples into the continuously flowing carrier liquid, which then the. Can convey liquid sample to the column, in particular for carrying out the method according to claim 1, characterized in that the injection device is a multi-part valve with a main inlet valve (4l), a main outlet valve (43), a main line (42) between the main inlet and - exhaust valves, with an additional inlet (36), with a sample line (46) which connects the additional inlet (36) to the main inlet valve (4l), with a valve device (42R) to at least a major part of the flow from the main line (42) via the sample line (46), and with a valve device (48) _/ to vent the sample line (46), the sample line (46) being in communication with the main outlet valve (43) and the additional inlet (36) , which is arranged immediately at the outlet valve (43), so that the sample line (46) represents a device to a liquid sample on the - 22- 5 098 20/1056 Input point close to the outlet valve (43) in the direction of the venting device (48), which is relatively is arranged far from the outlet valve (43). 5 · Injection device according to one of claims 3 or 4, characterized in that the diameter of the sample line (46) generally starts from one point becomes larger immediately at the outlet valve (4 3) in the direction of the inlet valve (4 3). 6. Injection device according to one of claims 3, 4 or 5, characterized in that the device to divert the flow through the sample line (46; 139), a static, the flow throttling device (42R; R) in the main line (42; 14o), in which no movable valve parts are provided. 7 · Injection device according to claim 6, characterized in that the average diameter the main line (42; l40) smaller than about half the smallest diameter of a section (l46a to l46d) of the Sample line (46; 139) is. 8. Injection device in the form of a multi-part valve device according to claim 3> characterized g e k e η η ζ ei chn e t that the device has a diaphragm valve, which has a branch part (112), a valve part (100), which provides means for adjusting a diaphragm actuation rod (105), and a thin metal diaphragm (ll4), which in connection with the actuating rod (IO5) and lines in the branch part (112) has a Ven tileinrichtung represents, and that the membrane (114) is held under pressure in full contact so that they see tight between rests against the branch part (112) and the valve part (100), whereby by means of the actuating rod (IO5) the membrane (ll4) is bent and a middle sealing surface into a - 23 - 5 0 9820/1056 ²³ 2A54046 Is brought to a position in which it rests snugly against a line (64) in the branching part (112). 9. Device according to claim 8, characterized in that the parts of the disc (1O6) _; which abut the branch part (112) and the valve part (100) have a deformable pad made of a material of a metal or a plastic, the thickness of the pad being less than about 0.005 cm (0.002 inches). 10. Device according to one of claims 8 or 9 «thereby characterized in that the membrane (114) has an annular flow path (1O8) which, together with dan Branch part (112) a channel for bypassing the sealing Surface (112a), and that the annular flow path (108) conduits (63, 65) in the branch part (112) connects. 11. Device according to one of claims 8 or 10, characterized indicates that the membrane (lld) can be removed from the device by the branching part (112) and the valve part (100) are separated from one another, and that the valve does not have any additional means of holding the membrane (114). 12. Device according to claim 8, characterized in that g e k e η n '- ζ ei c h η e t that the diaphragm valve is the main outlet valve (43) is which with the sample line (46) in connection stands. 509820/1056